Precancerous conditions of the anus
Anal intraepithelial neoplasia (AIN) is a precancerous condition that can develop in the anus. It is also called anal squamous intraepithelial lesions (SIL) or anal dysplasia.
AIN is when cells in or around the anus change and become abnormal. These cells are not yet cancer, but there is a higher chance they will become anal cancer if they aren’t treated.
Doctors describe AIN as either low grade or high grade, depending on how the cells look under the microscope. Low-grade AIN cells look much like normal cells and will often return to normal on their own. High-grade AIN cells look very abnormal under the microscope and usually don’t return to normal. High-grade AIN needs to be treated or it could develop into anal cancer.
Risk factors @(Model.HeadingTag)>
Human papillomavirus (HPV) infection is the most important risk factor for developing AIN. Having more than one sex partner increases your risk of developing an HPV infection. The following risk factors increase the chance that an HPV infection will not go away on its own and may develop into AIN:
- human immunodeficiency virus (HIV) infection
- weakened immune system caused by drugs given after an organ transplant
- having anal sex
- a history of vulvar intraepithelial neoplasia, which is a precancerous condition of the vulva
- a history of cervical intraepithelial neoplasia, which is a precancerous condition of the cervix
AIN does not usually cause any symptoms. Most people do not know they have AIN. If there are any symptoms, they may include:
- raised or scaly areas around the anus
Treatment options for AIN include:
- surgery such as electrosurgery or laser surgery
- topical creams such as 5-fluorouracil (5-FU, Efudex), imiquimod (Aldara, Zyclara) or trichloroacetic acid (Tri-Chlor)
photodynamic therapy (PDT)
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Fox PA . Treatment options for anal intraepithelial neoplasia and evidence for their effectiveness. Sexual Health. 2012.
Penn Medicine. Anal Cancer: The Basics. University of Pennsylvania; 2015: http://www.oncolink.org/includes/print_article.cfm?Page=2&id=9497&section=cancer_types.
Simpson JAD, Scholefield JH . Diagnosis and management of anal intraepithelial neoplasia and anal cancer. BMJ. 2011.